Endobronchially Implanted Real-Time Electromagnetic Transponder Beacon-Guided, Respiratory-Gated SABR for Moving Lung Tumors: A Prospective Phase 1/2 Cohort Study.

Purpose: Endobronchial electromagnetic transponder beacons (EMT) provide real-time, precise positional data of moving lung tumors. We report results of a phase 1/2, prospective, single-arm cohort study evaluating the treatment planning effects of EMT-guided SABR for moving lung tumors. Methods and Materials: Eligible patients were adults, Eastern Cooperative Oncology Group 0 to 2, with T1-T2N0 non-small cell lung cancer or pulmonary metastasis ≤4 cm with motion amplitude ≥5 mm. Three EMTs were endobronchially implanted using navigational bronchoscopy. Four-dimensional free-breathing computed tomography simulation scans were obtained, and end-exhalation phases were used to define the gating window internal target volume. A 3-mm expansion of gating window internal target volume defined the planning target volume (PTV). EMT-guided, respiratory-gated (RG) SABR was delivered (54 Gy/3 fractions or 48 Gy/4 fractions) using volumetric modulated arc therapy. For each RG-SABR plan, a 10-phase image-guided SABR plan was generated for dosimetric comparison. PTV/organ-at-risk (OAR) metrics were tabulated and analyzed using the Wilcoxon signed-rank pair test. Treatment outcomes were evaluated using RECIST (Response Evaluation Criteria in Solid Tumours; version 1.1). Results: Of 41 patients screened, 17 were enrolled and 2 withdrew from the study. Median age was 73 years, with 7 women. Sixty percent had T1/T2 non-small cell lung cancer and 40% had M1 disease. Median tumor diameter was 1.9 cm with 73% of targets located peripherally. Mean respiratory tumor motion was 1.25 cm (range, 0.53-4.04 cm). Thirteen tumors were treated with EMT-guided SABR and 47% of patients received 48 Gy in 4 fractions while 53% received 54 Gy in 3 fractions. RG-SABR yielded an average PTV reduction of 46.9% (P < .005). Lung V5, V10, V20, and mean lung dose had mean relative reductions of 11.3%, 20.3%, 31.1%, and 20.3%, respectively (P < .005). Dose to OARs was significantly reduced (P < .05) except for spinal cord. At 6 months, mean radiographic tumor volume reduction was 53.5% (P < .005). Conclusions: EMT-guided RG-SABR significantly reduced PTVs of moving lung tumors compared with image-guided SABR. EMT-guided RG-SABR should be considered for tumors with large respiratory motion amplitudes or those located in close proximity to OARs.

Optical scan and 3D printing guided radiation therapy - an application and provincial experience in cutaneous nasal carcinoma.

BACKGROUND: Single field Orthovoltage radiation is an acceptable modality used for the treatment of nasal cutaneous cancer. However, this technique has dosimetric pitfalls and unnecessary excessive exposure of radiation to organs at risk (OAR). We present the clinical outcome of a case series of cutaneous nasal tumours using a novel technique incorporating an optical scanner and a 3-dimensional (3D) printer to deliver treatments using parallel opposed (POP) fields. MATERIALS AND METHODS: The POP delivery method was validated using ion chamber and phantom measurements before implementation. A retrospective chart review of 26 patients treated with this technique between 2015 and 2019 was conducted. Patients' demographics and treatment outcomes were gathered and tabulated. These patients first underwent an optical scan of their faces to collect topographical data. The data were then transcribed into 3D printing algorithms, and positive impressions of the faces were printed. Custom nose block bolus was made with wax encased in an acrylic shell; 4 cm thick using the printed face models. Custom lead shielding was also generated. Treatments were delivered using 250 KeV photons POP arrangement with 4 cm diameter circle applicator cone and prescribed to the midplane. Dose and fractionation were as per physician discretion. RESULTS: Phantom measurements at mid-plane were found to match the prescribed dose within ±0.5%. For the 26 cases in this review, the median age was 78.5 years, with 15 females and 11 males. 85% of cases had Basal cell carcinoma (BCC); 1 had squamous cell carcinoma (SCC), one had synchronous BCC + SCC, and 1 had Merkel cell carcinoma. Twenty-one cases had T1N0 disease, 4 had T2N0, and 1 had T3N0. Dose and fractionation delivered were 40Gy in 10 fractions for the majority of cases. The complete response rate at a median follow-up of 6 months was 88%; 1 patient had a refractory tumour, and one patient had a recurrence. Toxicities were minor with 81% with no reported side effects. Three patients experienced grade 3 skin toxicity. CONCLUSIONS: Utilization of optic scanner and 3D printing technology, with the innovative approach of using POP orthovoltage beams, allows an effective and efficient way of treatment carcinomas of the nose with a high control rate and low toxicity profiles.

Impact of Pre-Treatment NLR and Other Hematologic Biomarkers on the Outcomes of Early-Stage Non-Small-Cell Lung Cancer Treated with Stereotactic Body Radiation Therapy.

INTRODUCTION: We evaluated the association of pre-treatment immunologic biomarkers on the outcomes of early-stage non-small-cell lung cancer (NSCLC) patients treated with stereotactic body radiation therapy (SBRT). MATERIALS AND METHODS: In this retrospective study, all newly diagnosed early-stage NSCLC treated with SBRT between January 2010 and December 2017 were screened and included for further analysis. The pre-treatment neutrophil-lymphocyte ratio (NLR), monocyte lymphocyte ratio (MLR), and platelet-lymphocyte ratio (PLR) were calculated. Overall survival (OS) and recurrence-free survival (RFS) were estimated by Kaplan-Meier. Multivariable models were constructed to determine the impact of different biomarkers and the Akaike information criterion (AIC), index of adequacy, and scaled Brier scores were calculated. RESULTS: A total of 72 patients were identified and 61 were included in final analysis. The median neutrophil count at baseline was 5.4 × 109/L (IQR: 4.17-7.05 × 109/L). Median lymphocyte count was 1.63 × 109/L (IQR: 1.29-2.10 × 109/L), median monocyte count was 0.65 × 109/L (IQR: 0.54-0.83 × 109/L), median platelet count was 260.0 × 109/L (IQR: 211.0-302.0 × 109/L). The median NLR was 3.42 (IQR: 2.38-5.04), median MLR was 0.39 (IQR: 0.31-0.53), and median PLR was 156.4 (IQR: 117.2-197.5). On multivariable regression a higher NLR was associated with worse OS (p = 0.01; HR-1.26; 95% CI 1.04-1.53). The delta AIC between the two multivariable models was 3.4, suggesting a moderate impact of NLR on OS. On multivariable analysis, higher NLR was associated with poor RFS (p = 0.001; NLR^1 HR 0.36; 0.17-0.78; NLR^2 HR-1.16; 95% CI 1.06-1.26) with a nonlinear relationship. The delta AIC between the two multivariable models was 16.2, suggesting a strong impact of NLR on RFS. In our cohort, MLR and PLR were not associated with RFS or OS in multivariable models. CONCLUSIONS: Our study suggests NLR, as a biomarker of systemic inflammation, is an independent prognostic factor for OS and RFS. The nonlinear relationship with RFS may indicate a suitable immunological environment is needed for optimal SBRT action and tumoricidal mechanisms. These findings require further validation in independent cohorts.

Bracing for impact with new 4R's in the COVID-19 pandemic - A provincial thoracic radiation oncology consensus.

As COVID-19 pandemic continues to explode, cancer centers worldwide are trying to adapt and are struggling with this constantly changing scenario. Intending to ensure patient safety and deliver quality care, we sought consensus on the preferred thoracic radiation regimen in a Canadian province with 4 new R's of COVID era.

Clinical Outcomes After Stereotactic Body Radiation Therapy for Early Stage Non-Small Cell Lung Cancer: A Single Institutional Study.

Introduction The standard of care for early-stage non-small cell lung cancer (NSCLC) is surgery. However, for medical inoperable patients stereotactic body radiation therapy (SBRT) is an alternative method. The aim of the study is to assess the overall survival (OS), progression-free survival (PFS) and local control (LC) of patients diagnosed with NSCLC in Manitoba, Canada, between 2013 and 2017 and managed with SBRT. Materials and methods This retrospective study included a total of 158 patients (60.13% of the population were females) that were diagnosed with stage I-II NSCLC and were treated with lung SBRT between 2013 and 2017 in Manitoba. Demographics and clinical data were retrospectively extracted from the electronic patient record. Kaplan-Meier and Cumulative incidence curves were used to describe the OS, PFS, and LC outcomes. Results From the 158 patients, 32 patients were treated with 60 Gy in eight fractions, while 121 patients were treated with 48 Gy in four fractions. Only 85 patients had biopsy-proven NSCLC. The median OS was 2.87 years (95% confidence interval [CI] 2.16-3.43). OS rates at one and two years were 85% and 66%, respectively. The median PFS was 2.03 years (95% CI 1.65-2.77). Furthermore, one-year and two-year PFS rates were 77% and 51%, respectively. Only 10 patients progressed locally at one year and 17 at two years, making the LC rate 93% at the one-year and 87% at the two-year mark. Conclusion These findings add to a growing evidence base supporting SBRT in the treatment of clinically suspected and biopsy-proven early-stage NSCLC patients.

Compliance and Outcome of Elderly Patients Treated in the Concurrent Once-Daily Versus Twice-Daily Radiotherapy (CONVERT) Trial.

INTRODUCTION: There is a lack of data on the efficacy and safety of concurrent chemoradiotherapy in elderly, limited-stage, patients with SCLC. METHODS: We compared outcomes of patients 70 years of age or older versus younger patients within the Concurrent Once-daily Versus twice-daily RadioTherapy (CONVERT) trial. Patients were randomized to receive 45 Gy/30 twice-daily fractions/19 days or 66 Gy/33 once-daily fractions/45 days concurrently with platinum-based chemotherapy. Overall survival and progression-free survival were evaluated using Kaplan-Meier methodology and Cox proportional hazards regression. RESULTS: Of 547 patients randomized between April 2008 and November 2013, 57 did not receive protocol treatment and were excluded. Of the 490 patients included, 67 (14%) were 70 years of age or older (median age: 73 years; range: 70-82). Fewer older patients received the optimal number of radiotherapy fractions (73% versus 85%; p = 0.03); however, chemotherapy compliance was similar in both groups (p = 0.24). Neutropenia grade 3/4 occurred more frequently in the elderly (84% versus 70%; p = 0.02) but rates of neutropenic sepsis (4% versus 7%; p = 0.07) and death (3% versus 1.4%; p = 0.67) were similar in both groups. With a median follow-up of 46 months; median survival in the elderly versus younger groups was 29 (95% confidence interval [CI]: 21-39) versus 30 months (95% CI: 26-35), respectively; (hazard ratio: 1.15, 95% CI: 0.84-1.59; p = 0.38). Median time to progression in the elderly versus younger groups was 18 months (95% CI: 13-31) versus 16 months (95% CI: 14-19), respectively (hazard ratio: 1.04, 95% CI: 0.76-1.41; p = 0.81). CONCLUSIONS: Concurrent chemoradiotherapy with modern radiotherapy techniques should be a treatment option for fit, older patients.

Clinical Characteristics and Prognosis of Primary Tracheal Cancer: A Single Institution Experience.

Background Primary tracheal cancers (PTCs) are rare and current evidence-based understanding is limited to retrospective reports and national databases. We present single institutional study of a historical cohort of PTC from Canadian provincial cancer registry database. Materials and Methods: After institutional research ethics board approval, all PTC patients diagnosed from 1980 to 2014 were identified through the Canadian provincial cancer registry. Demographic and tumor related factors were evaluated using descriptive statistics. Survival rates were estimated using the Kaplan-Meier method and cox hazard regression analyses were performed to identify predictors of disease-free survival (DFS) and overall survival (OS). Results: A total of 30 patients were included in the study. At presentation, 10 patients (33%) had only local disease, 14 patients (47%) had locoregional disease and the remaining 4 patients (13%) had distant metastasis. The majority of patients underwent primary radiation treatment. The overall survival rate was 30% at 2 years and 16% at 5 years. Patients receiving radical-intent therapy had better 2-year DFS and OS compared to patients managed with palliative radiotherapy and best supportive care (46%, 17% and 0%) (p=<0.001) and (50%, 23% and 0%) (p=<0.001), respectively. Radiotherapy resulted in a better 2-year OS and DFS (32% versus 14%) (p=<0.03) and (32% versus 0%) (p=<0.001), respectively. Conclusion: PTC is an uncommon neoplasm making the study of the disease technically and logistically challenging. Radical radiotherapy alone is curative option in inoperable PTC. Intent of treatment and radiotherapy were associated with superior survival outcomes.

Low-cost optical scanner and 3-dimensional printing technology to create lead shielding for radiation therapy of facial skin cancer: First clinical case series.

PURPOSE: Three-dimensional printing has been implemented at our institution to create customized treatment accessories, including lead shields used during radiation therapy for facial skin cancer. To effectively use 3-dimensional printing, the topography of the patient must first be acquired. We evaluated a low-cost, structured-light, 3-dimensional, optical scanner to assess the clinical viability of this technology. METHODS AND MATERIALS: For ease of use, the scanner was mounted to a simple gantry that guided its motion and maintained an optimum distance between the scanner and the object. To characterize the spatial accuracy of the scanner, we used a geometric phantom and an anthropomorphic head phantom. The geometric phantom was machined from plastic and included hemispherical and tetrahedral protrusions that were roughly the dimensions of an average forehead and nose, respectively. Polygon meshes acquired by the optical scanner were compared with meshes generated from high-resolution computed tomography images. Most optical scans contained minor artifacts. Using an algorithm that calculated the distances between the 2 meshes, we found that most of the optical scanner measurements agreed with those from the computed tomography scanner within approximately 1 mm for the geometric phantom and approximately 2 mm for the head phantom. We used this optical scanner along with 3-dimensional printer technology to create custom lead shields for 10 patients receiving orthovoltage treatments of nonmelanoma skin cancers of the face. Patient, tumor, and treatment data were documented. RESULTS: Lead shields created using this approach were accurate, fitting the contours of each patient's face. This process added to patient convenience and addressed potential claustrophobia and medical inability to lie supine. CONCLUSIONS: The scanner was found to be clinically acceptable, and we suggest that the use of an optical scanner and 3-dimensional printer technology become the new standard of care to generate lead shielding for orthovoltage radiation therapy of nonmelanoma facial skin cancer.

Clinical Implementation of a Model-Based In Vivo Dose Verification System for Stereotactic Body Radiation Therapy-Volumetric Modulated Arc Therapy Treatments Using the Electronic Portal Imaging Device.

PURPOSE: To report findings from an in vivo dosimetry program implemented for all stereotactic body radiation therapy patients over a 31-month period and discuss the value and challenges of utilizing in vivo electronic portal imaging device (EPID) dosimetry clinically. METHODS AND MATERIALS: From December 2013 to July 2016, 117 stereotactic body radiation therapy-volumetric modulated arc therapy patients (100 lung, 15 spine, and 2 liver) underwent 602 EPID-based in vivo dose verification events. A developed model-based dose reconstruction algorithm calculates the 3-dimensional dose distribution to the patient by back-projecting the primary fluence measured by the EPID during treatment. The EPID frame-averaging was optimized in June 2015. For each treatment, a 3%/3-mm γ comparison between our EPID-derived dose and the Eclipse AcurosXB-predicted dose to the planning target volume (PTV) and the ≥20% isodose volume were performed. Alert levels were defined as γ pass rates <85% (lung and liver) and <80% (spine). Investigations were carried out for all fractions exceeding the alert level and were classified as follows: EPID-related, algorithmic, patient setup, anatomic change, or unknown/unidentified errors. RESULTS: The percentages of fractions exceeding the alert levels were 22.6% for lung before frame-average optimization and 8.0% for lung, 20.0% for spine, and 10.0% for liver after frame-average optimization. Overall, mean (± standard deviation) planning target volume γ pass rates were 90.7% ± 9.2%, 87.0% ± 9.3%, and 91.2% ± 3.4% for the lung, spine, and liver patients, respectively. CONCLUSIONS: Results from the clinical implementation of our model-based in vivo dose verification method using on-treatment EPID images is reported. The method is demonstrated to be valuable for routine clinical use for verifying delivered dose as well as for detecting errors.